1. Technical Field
The present application relates to systems and methods for magnetic resonance imaging (“MRI”) and particularly to gradient coil assemblies and methods for their manufacture and use with magnetic resonance imaging systems.
2. Related Art
Magnetic resonance imaging, or nuclear magnetic resonance imaging, is primarily a medical imaging technique used most commonly in radiology to visualize the internal structure and function of the body. MRI is described, for example, by E. MARK HAACKE ET AL., MAGNETIC RESONANCE IMAGING: PHYSICAL PRINCIPLES AND SEQUENCE DESIGN (Wiley-Liss 1999), which is hereby incorporated by reference. The present disclosure relates to the magnetic resonance arts and specifically to horizontal (solenoid magnet) MRIs. It finds particular application in conjunction with medical magnetic resonance imaging and will be described with particular reference thereto. It is to be appreciated, however, that the disclosure also finds application in conjunction with other types of magnetic resonance imaging systems, magnetic resonance spectroscopy systems, and the like.
In magnetic resonance imaging, linear magnetic field gradients are used for spatial encoding. Gradient coils are used to produce these linear magnetic field gradients. Typical horizontal MRIs have horizontal cylindrical gradient coil assemblies that span the length of the device. Horizontal “open” MRIs have been developed for claustrophobic patients. Open MRIs have a split main magnet with a gap in the center and typically have split gradient coils as well to provide a clear opening for the patient. More recently, it has become desirable to include various treatment and imaging modalities in combination with MRIs and open MRIs, such as radiation therapy devices, biopsy needles, ablation devices, surgical devices, ultrasound, PET, SPECT, CT and others. For example, it would be desirable to place such instruments in the gap region of an open MRI. However, problems exist with this placement because of interference from various magnetic fields associated with the operation of the MRI as well as the problem of heating conductors the vicinity of the gradient coil.
Thus, there exists a need for improved MRI gradient coil assemblies and methods of manufacturing MRI gradient coil assemblies. There further exists a need for improved gradient coil assemblies for horizontal open MRIs, and gradient coil assemblies that allow for operation of a horizontal open MRI in conjunction with additional medical devices.